Process for fixing nitrogen by means of ferro-aluminium or other ferro-alloys.



l T ric OTTOKAR SEEPEK, o1 rams, Ensues, essienon To sooinrn eEnEnALn nns urrnunss, or PARIS, FRANCE.

PROCESS FOR FIXING BTITROGEN BY MEAN-S 0F FERRO-ALTILVIINIUM OR OTHER FEERO- 3.11161 3.

1,198,53fi5. Specification of Letter Patent,

No Drawing.

T 0 all whom it m my concern.

Be it known that I. O'riroKAn SERPEK, a

subject of the Emperor of Austria-Hungary,

and a resident of 12 Rue Roquepine, Paris, France, have invented a new and useful I Process for Fixing-Nitrogen by hileans of Ferro-Aluminium or other Ferro-Alloys, of which the following is a specification.

This invention relates to a process for fixing nitrogen, consisting in treating a. ferro-aluminium under heat with nitrogen either pure or in mixture with gases suit-' able or non-deleterious to the reaction. The ferroaluminium may be obtained. in any suitable-manner for exanipleby reduction of alumina or of its ores by means of carbon in presence of iron. In the case of utilization of ores of alumma, the ferroaluminium will contain either in the metallic state or in the state of OXlClS, different bodies such as silicon titanium, etc., which were contained in these ores. It may also contain carbon, particularly in the state of aluminium carbid. i

The two chief features of the process are (1) that the reaction can take place at a relatively low temperature, that it sullices to initiate the reaction at one point, and that it will then be propagated of itself through the'whole mass as a result a of the evolution of heat due to its exothermicity. I

The ferro-aluminium can be treated with the nitrogen or the nitrogenous gases in the pulverulent state after having been pounded to the suitable state of division. v In order to carry out the reactiomone .may merely heat thematerial as a preliminary step and leave the gases cold or the inverse procedure may be adopted; for ex ample the material'in the form of powder may be projected into a receptacle containing nitrogen or traversed by a current of nitrogen, in such a way that at least one of the reacting bodies (gas or solid material) shall be heated.

The heating of the reacting bodies may be carried out in any known manner; either electrically or by'any suitable fuel. Again the nitrogen might be led through tube to the bottom of a crucible filled with ferro -aluminium and ra1sed to" the desired temperature. The reaction begins at the place where the nitrogen enters the ferro-alumini Patented Sept. 19, 1916.

Application filed December :26, 1913. 5eria1E?o.807,915.

um. The zone of heat which is created at the bottom of the crucible extends toward the surface under very fayorable conditions.

In orderto facilitate the passage of the gas and to increase the surface of contact of the nitrogen with the product to be converted to nit-rid, it is advantageous "to divide the form-aluminium into small packets before charging it into the receptacle, either by Wrapping small quantities in pieces of paper which burn and leave the fritted material in the form of aggloinerates, or by using it directly iii the form of agglomerates prepared by means of any of the known agglomerants, fecula, starch, rye-flour, sodium silicate, etc. J

Instead of in the solid, state, the ferroaluminium might be treated in the liquid state-at the. moment when it has just been obtained if it be desired to take advantage of the heat which it still contains. In this case the mass can be poured into aconverter of the Bessemer type into which the nitrogen or the nitrogenous gases can be blown. The ferro-aluminlum treated contains as has already been stated, other elements such may beconducted in such amanner that it ing 40 per cent. of aluminium is pulverized,

raised to 1250" C. and subjected for three hours to the action of a current of nitrogen. The mass obtained contains 20 per cent. of nitrogen.

Example 2: There is treated in the same way a complex ferro compound obtained by treating in the electric furnace a mixture of aluminium ore. coke and iron; the coke and iron are added in the desired proportions with a slight excess in order that according to the composition of the ore, there may be a complete reduction of the alumina. iron 02nd, silica or titaniumoxid, and that the reduced elements may be dissolved in the iron in the proportion of 1 to 2 of iron to 1 of the other elements.

The mass obtained after a treatment similar to that in Example 1 contains 18 to 20% of combined nitrogen, if starting from bauxite having 60 per cent. of alumina.

The nitrogen-containing product obtained according to the above process can be treated by the processes already known for aluminium nitrid with a View to extracting there from either ammonia alone or ammonia and alumina. In the former case, in order to obtain ammonia there may be applied for example the method of attack by limited quantities of alkali or of alkaline aluininate which forms the subject of the prior United States Patent 1,040,439 dated October 8th 1912. But this attack may also be carried out by using hot water, preferably under pressure. The residue consisting of a mixture of metallic iron and alumina (possibly with silica, titanic acid, etc.) can be utilized for preparing a fresh ferro-aluminium or complex ferro compound which will fix fresh quantities of nitrogen in accordance with the process indicated above.

Again the complex ferro-aluminium which has been converted into nitrid may be treated with a View to obtaining therefrom pure alumina (with simultaneous evolution of ammonia) by the process of Bayer autoprecipitation, as modified in its application to.1aluminium nitrid (see United States Reissue 13509- January 7th 1913).

It is to be noted that the attack of the form compound by alkaline lyes or alkaline aluminate has for result to render soluble the Whole of the alumina (even thatarising from the decomposition of the cal-bid) with exclusion of the iron and impurities possibly contained in the primary material. The unattacked residue which consists chiefly of metallic iron can be separated with the greatest facility by decantation or filtration. This residue can be utilized for preparing a fresh complex fcrro compound by adding thereto further quantities of bauxite and of carbon.

In the following claims the expression aluminium nit-rid is to be understood 1n a sufficiently general sense to embrace complex nitrids containing chietly aluminium nitrid, as well as the latter alone.

I claim as my invention 1. A process for the preparation of aluminium nitrid, consisting in producing an alloy of form-aluminium by treating at a high temperature a mixture of carbon, aluminous material and iron, and then subjecting the ferro-alnminium thus produced to the action of nitrogen and heat of a less elevated temperature.

2. A process for the preparation of aluminium nitrid, consisting in producing an alloy of ferro-aluminium by treating at a high temperature a mixture of carbon, alumii'ious material and iron'and then subjecting. the term-aluminium produced to the actionfliof nitrogen, starting the reaction at one ,or more points and letting it propagate itself throughout the reacting material as a result of the evolution of heat due to its exotherraicity.

3. A process for the preparation oi aluminium nitrid, consisting in subjecting heated ferro-aluminium to the action of nitrogen by projecting the terro-alnminium in powdered form into a nitrogenous atmosphere.

4. A process for the preparation of aluminium nitrid, consisting in subjecting ferro aluminium reduced to powderto the action of nitrogen by projecting the powdered ferro-aluminium into a.nitrogenous atmosphere in the presence of heat.

5. A process for the preparation of aluminium nitrid. consisting in producing an alloy'of ferro-almninium by treating at a high temperature a mixture of carbon. aluminous material and iron, and then subjecting the ferro-aluminium thus produced to the action of nitrogen and catalytic material in the presence of heat of a lower temperature.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses.

OTTOKAR SERPEK.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

